On Fri, 6 Jun 2008, hadley wickham wrote:
On Fri, Jun 6, 2008 at 6:23 PM, Achim Zeileis
<[EMAIL PROTECTED]> wrote:
On Fri, 6 Jun 2008, Michael Friendly wrote:
In an R graphic, I'm using
cond.col <- c("green", "yellow", "red")
to represent a quantitative variable, where green means 'OK', yellow
represents 'warning'
and red represents 'danger'. Using these particular color names, in B/W,
red is darkest
and yellow is lightest. I'd like to find color designations to replace
yellow and green so
that when printed in B/W, the yellowish color appears darker than the
greenish one.
Is there some tool/code I can use to find these? i.e., something to
display a grid
of color swatches with color codes/names I can look at in color and B/W to
decide?
You could look at colors in HCL (i.e., polar LUV). For example, you could
choose a dark red HCL = (0, 90, 40) and a light green (120, 70, 90) and a
yellow somewhere in between.
How did you get to those numbers?
From scratch:
- hues 0 and 120 because Michael wanted red and green
- luminances 40 and 90 for sequential colors from dark to light
- chromas 90 and 70 for two reasons: only small differences in
chroma seemed necessary, and 90 and 70 are close to the maximal
values given the other two coordinates for each color.
I seem to remember there being
someway to convert rgb to hcl, but I can't find it.
I always use "colorspace" for that. See
example("polarLUV", package = "colorspace")
Best,
Z
Hadley
--
http://had.co.nz/
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